a scientist can manipulate the environment with these...something that is changeable in an experiment.

data

supporting evidence and is used to accept or reject the hypothesis

cell

viruses need to enter a _____ to reproduce

germ theory

it conforms to a well accepted scientific principle, scientists believe that colds are caused by viruses, which are microorganisms.

scientific theory

is an explanation of a set of related observations based on well supported hypotheses from several different, independent lines of research

the theory of evolution

all organisms derive from a single common ancestor and have changed and diverged through time, fundamental theory of biology,

experiments

how scientists gain evidence to objectively support a hypothesis, or fail to support

controlled experiments

to be sure that the experiment is unbiased

independent variable

the factor that is being tested

dependent variable

the factor that is affected by the independent variable-this is what is measured

standardized variables

the factors that are held constant for both groups in the experiment

control

the subject or group that is similar in every way to the experimental subject or group except that the control does not get the experimental treatment. act as baseline measurements. compare to experimental group

placebo

the "pill" that only acts as the treatment. not the actual treatment. given to the control group.

eliminate bias,

select groups at random

random assignment

ensures that each groups is relatively balanced in characteristics

good controls=strong inference

a strong statement about the truth of a given hypothesis possible when an experimental protocol greatly minimizes the number of alternative hypotheses that can explain a result

bias

human influence from the researchers or their subjects may unfairly influence...

observer bias

a researcher making consistent errors in the measuring and evaluation of results

blind experiment

avoids this by not letting the subjects know what experience is being predicted

double-blind experiment

both groups are unaware of either the hypothesis or whether the subjects are in the experimental group or control group

correlation

a relationship in the data. correlation does not mean causation

statistics

specialized branch of math, to determine significance of results

samples

small groups that are tested

statistical tests

used to extend the results from a sample to the entire population

sampling error

the effect of chance on experimental results is...

statistically significant

low probability that experimental groups differ simply by chance. Stats can't tell if an experiment was valid, only validate the data

peer review

researchers can submit a paper to a professional journal, paper is reviewed, it is rejected or returned for changes

primary source

how a peer review paper is submitted

secondary sources

bring published information to the public: newspaper and magazines, television and radio, the internet

Anecdotal evidence

based on experience not experimental data

water

for a planet to support life, an abundant amount of this liquid would have to be available